Your LWSS+6 glider carrier-flipping mechanism seems more complicated than necessary. It turns out that in this case, the standard 5-glider mechanism works, saving 4 gliders. Also, the 4-glider bookend-to-bookend-w/tub converter can be used instead of the 5-glider one, saving one more:

Incomplete synthesis of #188 that relies on still-incomplete #266. I realized later that exactly the same mechanism yields an incomplete #188 from still-incomplete #187, using 9 gliders, rather than the previous method that took 19:

The sudden-pre-block adder gives us a few additional syntheses: complete #366 and its cousin from #163, an incomplete #215 from also-incomplete #303, incomplete #228 from also-incomplete #266, and incomplete #316 from still-unknown #217 (from last month, but I don't think I posted it). Also, #228 can also be built much more cheaply from still-unknown #340:

I just optimized some syntheses of two naturally-occuring P2 oscillators (see Oscillator Synthesis thread), and noticed that another oscillators in the same group had a predecessor among the listed 17s. So here is #260 from 19 gliders, from last May:

Extrementhusiast wrote:#260 from a 12-bitter, in a similar style to #336:

While it's more expensive in this particular case, I'm sure the #336 mechanism will ultimately come in quite useful for other larger objects. I've had little success in doing much with spark coils. One thing I have tried to do (without success) is to lengthen one end - i.e. turn a spark coil into a piston, or a double piston into a triple piston, etc. (At present, even-sized pistons are buildable, but odd ones are not.) If such a method could be devised, one could even build a piston-extruding wick-stretcher (which someone suggested earlier on another thread).

#264 from 69 gliders, based on Dave Buckingham's synthesis of the super-pond (15.355). This can likely be improved, especially steps 4-8, which close and then re-open the exterior (prior to it being finally closed again at the end) just to make a minor tweak:

Sokwe wrote:A predecessor of #157 from two probably unsynthesized 8-bitters:

Oops! I hadn't noticed, at the time, that this was one of the ones I had synthesized during that batch, rendering the search for syntheses for those 18s unnecessary.

Sokwe wrote:A predecessor of #219 from a probably unsynthesized 21-bitter:

It occurred to me that the 21 might be hard to make, but #219 could be made instead from one of the hard 16s (see your synthesis of #274), whose arm could be flipped up into a feather. I decided to try the sudden-pre-block mechanism to do the top part of it, and surprisingly, this also just happens to do the bottom half as well, leaving only a blinker to clean up! Unfortunately, the resulting still-life has a tub at the bottom, rather than just an eater tail, and I haven't been able to remove it:

This is quite an impressive synthesis! I especially like the almost-square piece in the middle! Your second step shows a bun on the left. Converting and moving the wing down must go through several bookends first, so the last step in getting this bun takes 2 gliders, and you later show the bun flipped back into a bookend, costing another two. If the initial bookend is left in place, and is just flipped later, this only takes 3, saving 1 step and 1 glider, for a total of 105 gliders.

Extrementhusiast wrote:#336 from a trans boat on cap:

This can use a 2-glider bit-spark, reducing it by 1 glider (and similarly for your #260 synthesis):

Sokwe wrote:One of the steps in the last row doesn't seem to accomplish anything. It's easy to correct, however:

Oops! I don't know how I missed that. I usually re-run all the syntheses before I post them, to make sure all the "before" and "after" images match, but sometimes miss cases where "step n after" and "step n+1 before" don't!

Extrementhusiast wrote:Key step for #266:

I always got bogged down by both sides forming lines-of-four that joined, preventing the formation of the diagonal bits. It never occurred to me to LET them join (e.g. by building tables) and then breaking them junction later. This predecessor for #266 is obsoleted by my other synthesis (see below), but this still-life is still good to have around per se.

And now for new stuff:

#296 from 20 gliders, based on a 15 plus a new less obtrusive 5-glider hat double-extender. Matthias actually developed a method to build one of the 16s using a similar technique (using 14 gliders in 5 steps), so this one was also technically buildable from that. This also improves that synthesis by 9 gliders:

#194 from 47 gliders, based on a 41-glider 16 plus a less-obtrusive eater-to-gull converter. I have seen this mechanism used frequently to add hooks to other forming things, but I don't recall ever seeing it used as an eater-to-gull converter before:

#379 from 65 gliders, using Matthias's improved beehive-to-loaf converter. Much of the cos is because the converter is is one bit too close, so the snake has to be peeled back into a hook-w/tail and later put back. (This also solves 5 related derived ones not on the list - with one and/or both snakes turned into carriers.)

#308 from 18 gliders and #321 from 43 gliders. I first built #308 like #321 using the standard snake-to-domino+snake converter, but that required peeling the snake into a hook w/tail and vice versa, as above. I was able to re-tool the converter to use a different 3-glider pre-block generator, making it less obtrusive, and not need the peel/unpeel. This also allowed #321 to be built (needing the peel/unpeel, but now possible, at least). Unfortunately, this won't work for #297. The same mechanism also gives #311 from a 15:

There remain 35 other similar trivial derived still-lifes. Here is the list, in the unlikely event that any of these provides easier to synthesize than their listed cousins. (Most are connected to them by reversible conversions like snake<->carrier or beehive<->claw, so synthesis of either one automatically gives the other one, but there are occasionally exceptions, like the above synthesis, which can't be converted back to #382.)(UPDATE: there are also 2 others related to #253, with trans- and cis- carriers):

Improved synthesis of 16.1962 from 22 gliders (used to be 32, done a totally different way). This also reduces the associated 21-bit mold by 10 gliders. I can't remember, but this may also have been used as a predecessor for one of the other 16s or 17s:

Incomplete synthesis of #131, similar to #136 and related 16. There were four things that have to be changed to make this work. First, the initial 20-bit still-life needs to be synthesized (unresolved). (For the remaining three, the puffed-out bit in the loop interferes with nearby sparks.) Second, the boat-to-table conversion needs a wider spark. Third, the table-to-curl conversion requires a much more convoluted spark. Fourth, the bottom right construction step needs a different spark, which is possible, but I'm not sure how to make it. Shown are generations 1, 31, and 46, where the needed 6-bit spark is "magically" added to the bottom left in generation 31:

There are also now three empty columns in the table: 2x0, 2x6 and 3x8. (Solving any of #158 #244 or #292 will create a new empty column, while solving any of #100 #227 #253 #279 #281 or #390 will create a new empty row).

mniemiec wrote:Incomplete synthesis of #131, similar to #136 and related 16. There were four things that have to be changed to make this work. First, the initial 20-bit still-life needs to be synthesized (unresolved). (For the remaining three, the puffed-out bit in the loop interferes with nearby sparks.) Second, the boat-to-table conversion needs a wider spark. Third, the table-to-curl conversion requires a much more convoluted spark. Fourth, the bottom right construction step needs a different spark, which is possible, but I'm not sure how to make it. Shown are generations 1, 31, and 46, where the needed 6-bit spark is "magically" added to the bottom left in generation 31:

Here is the base still-life from 15 gliders, giving us #266 from 32, much better than my other one from 40 (and similarly improves two others derived from #266):(UPDATE: You already included this in the Oscillators thread in your eater-3 synthesis; plus, I just counted yours (which is essentially the same as mine) and it comes up to 30 gliders, so I'm going to need to figure out why my math is wrong.)

extrementhusiast wrote:I only note one problem, which is the synthesis of the initial SL. One problem apparently does not matter, as an alternate solution is also presented. And I don't even see the other two problems.

In my solution two of the problems have been fixed. (If you compare this solution with the original still-life, most of the steps are identical, but two of the major steps have had alterations to the spark-producers).Unfortunately, one problem remains, the step in the bottom right corner. It requires a spark (also at the bottom right corner of that step) that I don't know how to provide. Any ideas?

Extrementhusiast wrote:#253 (rather, a trivial variant of such) done in a slightly different way:

Extrementhusiast wrote:Trivial variant of #329 from an 11-bitter:

These are much smaller and cleaner than mine (see below).

Extrementhusiast wrote:Additionally, my method for #266 only takes 30 gliders, not a number over 40.

I'll have another look at where I got my numbers.

And now for new stuff:

mniemiec wrote:#253 from 23 gliders, based on a 15.UPDATE: This doesn't quite work, as one of the final steps was broken. This is now demoted to "potential synthesis":

I had used this method (via eater), because the one I had tried previously (via barge) didn't quite work. Since this one doesn't work (and I can't get it to work), I went back to the previous attempt, and managed to fix it. #253 from 31 gliders, via its cousin from 26 gliders:UPDATE: Extrementhusiast's version is much smaller.

Sadly, the above method can't be used for #330 or #331, as the related predecessors aren't stable. What would be very useful is a tool that converts an inducting block (or table, or anything else similar) into a siamese carrier (i.e. an attached bit plus a pre-block). That would solve these two, plus several others that have come up before - or even from an inducting eater or snake, to perhaps solve #166.

#340 from 18 gliders. Some of the sparks could probably be sped up. This also greatly reduces #228 from 45 to 24 gliders:

At this point, my count is 67 basic still-lifes unsynthesized (or only partially synthesized), plus 33 trivial ones derived from these, so there are now only 100 left to go, only 2/3 of which require any actual work!UPDATE: Now down to 62 plus 32.

Extrementhusiast wrote:I only note one problem, which is the synthesis of the initial SL. One problem apparently does not matter, as an alternate solution is also presented. And I don't even see the other two problems.

In my solution two of the problems have been fixed. (If you compare this solution with the original still-life, most of the steps are identical, but two of the major steps have had alterations to the spark-producers).Unfortunately, one problem remains, the step in the bottom right corner. It requires a spark (also at the bottom right corner of that step) that I don't know how to provide. Any ideas?

I'd have to check, but I think you solved your own problem, and that the lower solution was another line of inquiry that didn't entirely pan out.

EDIT: Sokwe covered this at pretty much the same time.

mniemiec wrote:Sadly, the above method can't be used for #330 or #331, as the related predecessors aren't stable. What would be very useful is a tool that converts an inducting block (or table, or anything else similar) into a siamese carrier (i.e. an attached bit plus a pre-block). That would solve these two, plus several others that have come up before - or even from an inducting eater or snake, to perhaps solve #166.

I used the following step in my griddle-with-hook-and-tub synthesis (on page eight in the other thread) that may give some ideas:

Extrementhusiast wrote:I'd have to check, but I think you solved your own problem, and that the lower solution was another line of inquiry that didn't entirely pan out.

No. The bottom left step is part of the critical path, and incomplete. The first image on the bottom row shows most of the synthesis, omitting any bottom-left sparks. The second shows that same pattern advanced 31 generations - with the crucial spark added in "magically" by hand. The third step is the desired result, at generation 46.

Extrementhusiast wrote:Also, I count 59 still lifes, not 62, although I may have deleted a few when they should not have been. (I'm not currently keeping track of the trivial variants.)

I'll try to put together an abridged list of what is still missing from my lists. Then we can compare lists to see whether some have been removed that shouldn't have, or if I have some that should have ben removed, but weren't.

Extrementhusiast wrote:I'd have to check, but I think you solved your own problem, and that the lower solution was another line of inquiry that didn't entirely pan out.

No. The bottom left step is part of the critical path, and incomplete. The first image on the bottom row shows most of the synthesis, omitting any bottom-left sparks. The second shows that same pattern advanced 31 generations - with the crucial spark added in "magically" by hand. The third step is the desired result, at generation 46.

I'm a bit confused as to why you think it's that way, because if I labeled your RLE like this:

Most of the ones still left on the list look like they belong there -- fairly delicately balanced, with no obvious way to modify a protruding corner to subtract one bit and get to a known predecessor (with any likelihood of getting back again).

A few of them I'm surprised have lasted so long, though, like #363, #381, #384, #385, and maybe #361. Seems like their continued presence must mean there's no known way to convert a protruding snake into an eater. Is this true?

I just spent a few minutes applying sparks to snakes, and quickly got in over my head -- I don't have a very good mental spark library, I guess. But certainly snakes don't seem to be that difficult to make adjustments to...?

Sokwe wrote:I'm not seeing it. In fact, the entire bottom row seems irrelevant since the synthesis appears to be complete in the third row.

Extrementhusiast wrote:I'm a bit confused as to why you think it's that way, because if I labeled your RLE like this:

Please accept my profound apologies for all the confusion I've caused over this synthesis. When I first created the synthesis for #131, I just took Matthias's related synthesis file and flipped everything over, concentrating on fixing all the steps that were broken. When I found the last one that I couldn't fix, I had spent so much time trying to make it work, I concluded that this synthesis wasn't fully functional yet, so I didn't even notice that this was merely an alternate synthesis path that didn't need to be fixed. The last row is, indeed, totally superfluous (so the fact that it can't be fixed is moot), as has been repeatedly pointed out, but I kept missing that. Thanks for constantly hammering me over the head with this (including the red crayon drawing) until I finally got what you were trying to say.

mniemiec wrote:I'm trying my best not to sound like a typical Internet commenter, so I sincerely apologize if I come off as being a bit blunt and/or rude with this post.

I try to avoid being totally dense, but it does seem to happen on occasion, and in this case, bluntness and "let me say this again in small words, slowly, so you can understand what I am saying" were totally necessary and appropriate. I'm just sorry that it took so long and wasted so much of everyone else's time.

mniemiec wrote:Incomplete synthesis of #131...

Extrementhusiast wrote:Solution for that 20-bitter, using part of pretty much the same method as #143:

A block+boat can be added to a hat-like object directly in one step, saving one glider:

Extrementhusiast wrote:The same method used to solve #106 can be used to partially solve #331 (and potentially improve #329 and/or #330):

I don't know how to make any of the still-life predecessors. There is a synthesis of a cousin of this one, although the inside tab is on the bottom rather than the top, making it useless for this method. On the plus side, this converter can actually be done with one less glider, which also reduces #106 by one:

This is cheaper than your previous synthesis. It also makes the carrier-based cousin even cheaper, since rather than making it from #235 (at cost+6), it can be made earlier via the carrier-based cuphook (at cost+2).

Extrementhusiast wrote:Key step for #266:

Extrementhusiast wrote:Additionally, my method for #266 only takes 30 gliders, not a number over 40.

mniemiec wrote:I'll have another look at where I got my numbers.

I had developed a completely different synthesis for it from 40 gliders, at around the same time (and didn't see yours until several days later). I also had yours written down as 32 gliders, based on your "Key step" post, and was confused by the count, since your version in the Oscillator Synthesis thread had only 30. I finally figured it out - you used two 3-glider domino sparks in the "Key step" post, but two 2-glider ones later, reducing it from 32 to 30.

Extrementhusiast wrote:Also, I count 59 still lifes, not 62, although I may have deleted a few when they should not have been. (I'm not currently keeping track of the trivial variants.)

I just compared my version of the stamp collection at the front of this thread with the one currently up there (as of 2/24), and noticed that you listed 3 completed that I didn't:#131 was, in fact, solved (see above), so this was due to me being stereotypically blond.#268 is a partial synthesis, based on as-yet-unsynthesized #187. #316 is a partial synthesis, based on as-yet-unsynthesized #217.

dvgrn wrote:I just spent a few minutes applying sparks to snakes, and quickly got in over my head -- I don't have a very good mental spark library, I guess. But certainly snakes don't seem to be that difficult to make adjustments to...?

Actually, only the snake is necessary. The rest of the base still-life can be removed, resulting in an 18-bit still-life synthesis. If you replace the eater with a tub, you get a 15-bit still-life, and it's much cheaper than the previous way of making this, so this is a useful converter (and, surprisingly, not one I was aware of). The only one I have listed for converting a snake into a curl is from the side, not from the end.

Excellent! One converter that was missing was a way to convert a snake into a tail-first eater. There are ways of doing it from a cis-carrier, and that can be made easily enough from a snake, but all too often, either the carrier isn't stable in that position at all (as in this case), or requires a ridiculously large amount of temporary scaffolding to hold it in place so it can be converted (and I'll need to go through many similar existing syntheses to see if this can improve them).

Extrementhusiast wrote:#263 from a 15-bitter:

I had tried a similar approach, but kept running into the problem that the traditional (and expensive) beehive-to-loaf converters fail if the beehive is attached at the bottom. Yours is cheaper, and actually requires the attachment, so it should provide a nice complement to the other converters. This looks obvious in retrospect, and I've seen it used in other contexts, but I don't recall seeing it being used as a beehive-to-loaf converter before.

The above mechanism also enables the construction of several circular pseudo-objects.

Almost complete synthesis of 23-bit period-2 pseudo-oscillator from 88+n gliders. (This was supposed to be the 21-bit one, but I only noticed it was the wrong size after it was finished. I'm glad I did it, because it provided most of the vital pieces for the next synthesis):

-- which is not quite good enough, and it seems to indicate that converting a glider into a boat at the last minute will always overstep the boundary in this same way. One way of stating the problem is that it's hard to turn on that last cell at the point of the boat, without also ending up with three ON cells in a row along one edge or another -- and three ON cells means you need a birth-suppressing cell in a forbidden location beyond the edge.

It would be nice to be able to use a diagonally symmetric reaction, since the final result is symmetrical. But to turn on the point of the boat, you have to have an ON cell in the center of the boat, one tick before -- and turning that cell ON and then OFF again seems to need more neighbors than are actually available in that constricted space. The symmetric three-cell combinations that could turn that cell ON don't seem to be workable, and the asymmetric ones tend to cause side-effect births beyond the boundary.

But so far I haven't quite been able to prove that it can't be done, so don't let me discourage anyone...! Do you have an almost-working sample reaction that makes this look less impossible?

-- which is not quite good enough, and it seems to indicate that converting a glider into a boat at the last minute will always overstep the boundary in this same way. One way of stating the problem is that it's hard to turn on that last cell at the point of the boat, without also ending up with three ON cells in a row along one edge or another -- and three ON cells means you need a birth-suppressing cell in a forbidden location beyond the edge.

It would be nice to be able to use a diagonally symmetric reaction, since the final result is symmetrical. But to turn on the point of the boat, you have to have an ON cell in the center of the boat, one tick before -- and turning that cell ON and then OFF again seems to need more neighbors than are actually available in that constricted space. The symmetric three-cell combinations that could turn that cell ON don't seem to be workable, and the asymmetric ones tend to cause side-effect births beyond the boundary.

But so far I haven't quite been able to prove that it can't be done, so don't let me discourage anyone...! Do you have an almost-working sample reaction that makes this look less impossible?

Something a bit more reasonable could be to start with a block and then turn that into a boat.

You can save one glider from the bottom one (#363). The new standard 3-glider boat-to-block method (from behind) won't work here, so you use a 4-glider one. However, the older standard 3-glider from-the-side method does work:

Sadly, this beehive-to-loaf method doesn't generalize to loaf-to-mango (which would be useful for #227, which looks fairly similar). An adaptation of this beehive-to-loaf converter gives us #316 from 26 gliders (and also an alternate synthesis of #328 from 28 gliders, but other ways are cheaper). It's likely that the convoluted way of adding the bottom claw from 9 gliders can be improved:

There seem to be certain kinds of structures that are unusually difficult to synthesize. For example, 12 of the remaining 50 still-lifes (almost a quarter of them) have a snake-bridge-with-domino protruding from one side:

Perhaps finding general-purpose ways of adding these could remove multiple objects from the list at once.

Extrementhusiast wrote:#186, #191, and #341 are surprisingly similar to one another:

Not to mention one of the four remaning unsolved 21-bit P3s (i.e. that corner on trice-tongs)

Extrementhusiast wrote:Also, I think the mismatch in numbering came from me taking dvgrn's suggestion of deleting SLs from the list if they were synthesized from another SL on the list, while you do not do such a thing.

I don't remove them, for two reasons. First, the objects are not, in fact, synthesizable from scratch yet. Second, there may still be alternate ways of making the objects. In fact, I believe that a few objects that had originally been partials (built from other unbuildable ones) have been solved a different way, while their original predecessors remain unsolved - and they would not now be solved if they had been removed froam consideration. (Of course, I did this same exact thing when creating the list initially - by removing all the objects that could be trivially made from ones on the list, so I suppose I'm not being terribly consistent!)

-- or any number of variations on the same theme. But I don't know how to build a complex spark like that, short of writing a search program to collide gliders at random (and/or maybe gliders and small still lifes) and look around the edges for the right shape of dying spark.

Might there be any reasonably easy way to convert the current automatic synthesis database into pictures of sparks, or some kind of lookup table, so that I'd have a shot at being able to figure out what's already known? I do enjoy incompetently mucking around with glider syntheses now and then, but at this rate I probably won't ever manage to commit enough detail to memory to know how to apply "standard tools" consistently to new problems.

-- or any number of variations on the same theme. But I don't know how to build a complex spark like that, short of writing a search program to collide gliders at random (and/or maybe gliders and small still lifes) and look around the edges for the right shape of dying spark.

dvgrn wrote:Might there be any reasonably easy way to convert the current automatic synthesis database into pictures of sparks, or some kind of lookup table, so that I'd have a shot at being able to figure out what's already known? I do enjoy incompetently mucking around with glider syntheses now and then, but at this rate I probably won't ever manage to commit enough detail to memory to know how to apply "standard tools" consistently to new problems.

Since I was in that position, I will say this: looking at a whole bunch of syntheses and finding common subpatterns between syntheses should help get you familiar with at least the most common ones. Also, I've found that different people use the same subpatterns differently, so look at example syntheses from all three of us. (I've found that I use the same components in different ways, Niemiec uses them in pretty standard ways, and creates new components when those don't work, and Sokwe tends to be in between.)

dvgrn wrote:Might there be any reasonably easy way to convert the current automatic synthesis database into pictures of sparks, or some kind of lookup table, so that I'd have a shot at being able to figure out what's already known? I do enjoy incompetently mucking around with glider syntheses now and then, but at this rate I probably won't ever manage to commit enough detail to memory to know how to apply "standard tools" consistently to new problems.

At some point when I have time, I am thinking about converting my synthesis tools into a reasonable humanly-readible form. Unfortunately, there are currently around a thousand tools in the human-usable tools (and some have many variants - I have converted two so far, "add block" and "add boat", and each of these has dozens of variations), plus almost as many machine-readible variants of these used by the synthesis expert system. These will take a long time to convert (and as I just this past week started a new job that's currently 60 hours a week - after being unemployed for a few years and having lots of spare time for Life - it's not anything I will have time to do anytime soon.

Extrementhusiast wrote:Since I was in that position, I will say this: looking at a whole bunch of syntheses and finding common subpatterns between syntheses should help get you familiar with at least the most common ones. Also, I've found that different people use the same subpatterns differently, so look at example syntheses from all three of us. (I've found that I use the same components in different ways, Niemiec uses them in pretty standard ways, and creates new components when those don't work, and Sokwe tends to be in between.)

I would tend to agree with this. I usually look at standard tools, and where they "ought to fit", and if they don't quite work, I try to find ways to adapt them to fit custom geometries. Over the past year, I've been getting much better at being able to backtrack things a few generations to figure out just where a spark needs to be added or suppressed to make something work. I've also found that the fact that we all tend to look at things in slightly different ways makes it much easier for us to cover different areas, and for one of us to find easy things that others find difficult.

Extrementhusiast wrote:I can tell that these syntheses are requiring (at least at first) techniques that are much more complex than before. Fortunately, I'm getting a feel for these more complex syntheses.

This is not surprising. The list I posted here (and similarly, with the 16-bit ones) started out with 90% of the objects being pruned by the expert system, and a few other easy ones removed by hand before being posted. From the remaining ones, as the low-hanging fruit get removed, typically in order of difficulty, whatever is left should naturally become more and more difficult. Since we all seem to be learning from the experience, many that seemed impossible earlier may now seem difficult but possible.

This is yet another possible route to get to #217, from #266. The top row shows the almost-synthesis at generations 0, 22, 24, and 25. A one-bit spark is missing from generation 24. The second row shows a possible way to get there from generation 22, but I haven't figured out any viable predecessors any further back: